**Multiply :**

**(i) 5x ^{2} – 8xy + 6y^{2} – 3 by – 3xy**

**(ii) 3 – (2/3)xy + (5/7)xy ^{2} – (16/21)x^{2 }y by – 21x^{2}y^{2}**

**(iii) 6x ^{3 }– 5x + 10 by 4 – 3x^{2}**

**(iv) 2y – 4y ^{3} + 6y^{5 }by y^{2} + y – 3**

**(v) 5p ^{2} + 25pq + 4q^{2} by 2p^{2} – 2pq + 3q^{2}**